This invention relates to a spinning machine having several spinning stations for the spinning of yarns from slivers which are fed to the spinning stations in cans, guiding devices for the slivers being arranged between the cans and the spinning stations.
The feeding of the fiber material to be spun in the form of slivers disposed in cans is known, for example, in the case of open-end spinning machines. In the case of the machines currently on the market, the slivers are withdrawn directly by the sliver feeding device of the individual spinning stations from cans standing in front of and partially below the spinning arrangement.
It is also known (German Patent Document DE-C 23 35 740) to arrange the cans, in the case of open-end spinning machines, on a platform above the spinning machine and to feed the slivers to the spinning stations through guide tubes. These guide tubes, which are provided with baffles, are to serve as intermediate storage devices which, because of a special construction, are fed by a continuously running feeding device nevertheless in an intermittent manner. The sliver is then to be guided through the respective guide tube essentially free of tensile stress.
The feeding of the fiber material in the form of slivers made available in cans is known also in the case of other fast-running spinning machines, for example, in the case of wind-around spinning machines or air spinning machines. These are as a rule one-sided machines, in the case of which the slivers are fed to the spinning stations from above and are taken out of the cans deposited on the rear side of the spinning machine. In this case, guiding devices for the slivers are provided in the form of pulleys and guide rods.
It is also known (German Patent Document DE-PS 817 572), in the case of ring spinning machines, to feed slivers in cans, in which case the cans are deposited on platforms or in a space above the spinning machine. This results in relatively long paths with one or several vertical sections which result in the risk that the slivers may hang out; that is, are uncontrollably drafted because of their inherent weight. Such an arrangement is therefore possible only for slivers which have a relatively coarse size and therefore a relatively high strength.
It is also known (British Patent Document GB-PS 1 015 780) to feed the slivers from the cans to the drafting units of the spinning stations of a ring spinning machine by means of guide aprons, in which case two guide aprons respectively receive a sliver between their runs which extend in parallel to one another. In the case of this construction, the cans are deposited next to the ring spinning machine while leaving an aisle. The slivers are withdrawn from the cans, are then guided downward between the cans, are guided inside the floor of the ring spinning machine and are then guided inside the ring spinning machine upward to the drafting units.
However, the spinning of slivers with coarse sizes is very difficult on ring spinning machines. Since ring spinning machines have only a relatively low delivery rollers of the drafting units--while taking into account the required draft--must run very slowly, that is, at rotational speeds of one revolution per minute and less. Technically, it is extremely difficult to let long shafts, as represented by the feeding rollers of drafting units, run with sufficient precision at such low rotational speeds. There is the danger that these shafts rotate only jerkily so that then no controlled draft will be obtained. The feeding in cans of the fiber material to be spun in cans has therefore not been carried out successfully in practice in the case of ring spinning machines.
It is an object of the invention to develop a spinning machine of the initially mentioned type such that particularly fine slivers can be spun without the danger of faulty drafts of the slivers during the transport from the cans to the spinning stations.
This object is achieved in that the guiding devices comprise drivable guide aprons which run into the transport direction of the slivers and the transport surfaces of which receiving the slivers are covered at least along a part of their length by means of essentially stationary elements which have sliding surfaces facing the transport surfaces.
In the case of the development according to the invention, it is achieved that the slivers are supported but are nevertheless moved in the transport direction. As a result, it is possible to feed also relatively thin slivers in cans, that is, slivers with sizes of approximately Nm 0.4 to 0.8. In this case, these fine slivers can also be transported along larger sections in the vertical direction. It is therefore possible to carry out a can feeding also in the case of ring spinning machines because, as a result of the slivers with the fine sizes, while the draft is taken into account, the feeding roller pairs of the drafting units still run at a sufficiently high speed so that a uniformly round rotating is ensured. As a result of this can feeding, it will then be possible, in the case of ring spinning machines, to do without a machine connected in front of it, specifically a flyer. In the case of other spinning machines which are provided with drafting units into which the slivers enter, it is possible to feed finer slivers so that then the drafting units may be simplified. For example, in the case of machines of this type, there exists the possibility to use, instead of the five-cylinder drafting units, the three-cylinder drafting units which are customary in the case of ring spinning machines today.
Also in the case of open-end machines, the feeding of finer slivers results in advantages because then the opening-up work for the separating of the fibers will be less so that the fibers are processed more carefully during the opening-up. It is therefore possible to spin finer yarns with less damaged fibers so that the yarns have a higher quality.
Mainly, the elements with the sliding surfaces are assigned to essentially vertical sections of the guide aprons. The sliding surfaces are loaded by a force of approximately 0.2N to approximately 1.5N in the direction of the guide apron. The contact pressure force onto the sliver is therefore very low. It only has the purpose of securely guiding the sliver and avoiding faulty drafts, in which case the sliding guiding results in a certain smoothing.
In a particularly advantageous development of the invention, the sliding surfaces are a component of strip-type skids. In an embodiment, two skids are provided which are arranged vertically at a distance from one another, which are pressed apart by elastic devices and which are each assigned to one side of the machine. As a result, the expenditures can clearly be reduced.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.